The present invention relates to a process and a device for measuring spacing at a paper machine headbox.
The water content and thus, the consistency of the pulp mixture in the headbox of a paper machine are normally set at the headbox feed by altering the slice gap. In a multi-layer headbox, measuring the slice gap is even more important because it means that dewatering behavior in the wire section can be controlled even more efficiently for multi-layer operations. The following methods of measuring, all of which take measurements indirectly because of the prevailing difficulties, are already known for the tissue machine: (a) measuring at the lip adjustment drive, without taking account of any deformation of the thin lips, which are subject to enormous loads because of the high pressures in the headbox, and (b) measuring using thin, mechanical levers which either relay the position of the lip back out of the slice gap area or through the side wall to the outside. These levers are complicated to install and the results of measurements taken correspondingly unreliable.